Internal combustion engine



April 11, 1933. G. W SMWH, JR 1,903,485

INTERNAL COMBUSTION ENGINE Filed NOV. l0, 1930 IA' l/'ENTOR A TTORNE YGW. 5MlTH,Jr.

Patented Api.' 11, 1933 UNITED STATES PATENT OFFICE GEORGE W. SMITH,JB., OF CLEVELAND, OHIO,ASSIGNOR TO THE WHITE MOTORCOM- PANY, 0FCLEVELAND, OHIO, A. CORPORATION OF OHIO INTERNAL COMBUSTION ENGINEApplication led November 10, 1930. Serial No. 494,556.

This invention relates to internal combustion engines of the poppetvalve type, and more particularly to valve seats for such engines.

It is an object of my invention to provide a new construction for avalve seat unit for an internal combustion engine which can be employedto overcome many of the difficulties encountered in securing valve seatmaterials in engine parts constructed of dierent materials.

As hereinafter disclosed, a unit constructed in accordance with myinvention can be successfully employed to eli'ect the securement in anengine part of a body of valve seat material having a materiallydilerent coeiiicient of thermal expansion than the engine part.

My invention further possesses utility in instances in which it isdesired to use a costly valve seat material, the units employed in suchinstances being constructed with small valve seat portions, and withbase portions of suitable design to properly support the valveseatparts.

My invention also possesses utility in instances in which it isnecessary or desirable to secure the valve seat material to the partwhich supports it by a brazing or similar bonding process, since itpermits the bonding process to be performed in a facile manner withsmall parts.

Other uses of my invention will occur to those skilled in the art towhich my invention pertains.

In the drawing:

Figure 1 is a fragmentary side elevation, partly in section, of anengine equipped with valve seat units constructed in accordance withthis invention.

Figure 2 is a fragmentary bottom plan view of the cylinder head of theengine shown in Figure 1.

Figure 3 is a perspective view, drawn to a relatively large scale, of anunfinished part of a valve seatrunit of the type illustrated in Figures1 and 2.

Figure 4 is a perspective View, drawn to the same scale as Figure 3, ofa second unfinished part of a valve seat unit of the type illustrated inFigures 1 and 2, and

into the cast-iron .cylinder head. 11 adjacent the interior end'of eachexhaust vpassage 13, there is a valve seat insert or? unit 16 consistingof a threaded outer. steel' part 17 and an inner aluminum-bronzevalve'se'at part 18 affixed to the steel part 17 in 'such a manner asnot to become detached therefrom by unequal expansion or contractionofthe metals of thel two parts.

The aluminum-bronze alloy valve'seat parts 18 are constructed isparticularly adapted for use in valve seats, but .due to its relativelyhigh coetlicient of thermal of which the expansion has been found inpractice to be exceedingly dilicult to secure in place in a castironpart in the form of an insert. In the present construction thediliiculty of securing the aluminum-bronze valve seat parts within thecast-iron cylinder head is overcome by the addition to the valve seatunits of the external steel parts 17 which have a coeiiicient of thermalexpansion similar to that of cast iron, and which for that reasonmaintain a tight threaded engagement with their seats 19 in the cylinderhead throughout the range of temperatures to which the inserts and theadjacent port-ionsof the cast-iron cylinder head are subjected.

In the initial construction of an insert 16, an aluminum-bronze 18a ofthe form shown in Figure 3 is securely bonded within an unthreaded steelpart 17a as shown in Figure 4. This may be accomplished by brazing orsoldering nthe aluminum-bronze part to the steel part, the steel part insu'ch case being constructed withan inner diameter a few hundredths ofan inch larger than the outer diameter of the aluminum-bronze part so asto provide a space for the reception of the bonding material.

Under one process, the aluminum-bronze part 18a and the steel part 17 aare first coat- -ed with a spelter of brass by dipping them in a moltenbath of that metal upon which is floated a flux of borax. Thealuminumbronze part is then placed in an assembled position Within thesteel part, and the two parts immersed in the molten spelter bath for aperiod of several minutes, after which the two parts are withdrawn andallowed to cool.

Under a second process, the parts 17a and 18a are placed within theflame of a gas torch and heated to a temperature of about 1450 degreesFahrenheit, the iame being adjusted at the termination of the heatingperiod so as to maintain the parts at such temperature. The innersurfacesof the steel part, and the outer peripheral and bottom surfacesof the aluminum-bronze part are then coated with a flux of fused boraxwhich is spread'over the surfaces of the parts in any suitable mannerafter being reduced to a molten state by the heat of the flame;following which, the steel part is coated with a silver solderconsisting of approximately 45 per-cent silver, 25 per cent zinc and 30per cent copper, the solder like the ux being applied in a molten stateafter being melted by the flame. The aluminum-bronze part is then placedWithin the steel part and the annular space between the two parts filledwith molten silver solder of the same character as .that previouslydescribed, the solder as before being reduced to a molten state by theheat of the ame. Upon completion of the process, the flame is.extinguished and the parts allowed to cool.

A better bond is obtained in the last described process if the innersurfaces of the steel member 17 a are protected from the flame duringthe initial part of the process by means of a steel member 20 of theform illustrated in Figure 5. In using the protector member 20, the fluxand silver solder used in coating the inner surfaces of the steel part17a' are applied through apertures 21 in the upper flange of theprotector member, and continuously spread over the inner surfaces of thepart by rotation of the protector member, and by means of a special toolinserted through the central opening in the protector member. After thesteel part has been coated with solder, the protector member is removed,the

aluminum-bronze part inserted, and the an-y nular space between the twoparts filled with solder as before described.

Following the bonding of the aluminumbronze, part 18a within the steelpart 17a, the excess bonding material adhering to the external surfacesof the insert is removed, and the outer peripheral surface of the part17a formed with threads. The insert is then screwed into a threaded seat19 in the cylinder block by means of a special tool which engages theradial projections 22 of the part 18a. After the insert has been set uptightly in the cylinder head, the radial projections 22 are partiallyremoved, and the seating surface 23 added. Should an insertbecomeunserviceable, it may be removed by the special tool above mentioned,and a new insert installed. f

Although the inserts 16 have been described as being screwed into thecylinder block, they may be secured in place in some other manner, suchas by brazing or shrinking them within suitable seats in the cylinderhead. Thevalve seat parts 18 may also be secured within the steel parts17-by various other processes than those described, as for instance byWelding, or by a process similar to that disclosed in United StatesPatent Number 976,456.

The inlet valves 14 are provided with seats 24 formed Iin the cast-ironcylinder head 11, but if desired may be provided with valve seat insertssimilar to the inserts 16. Such construction is, however, not warrantedin the present engine as the inlet valves and their seats are notsubjected to sufliciently high temperatures as to materially lessentheir resistance to wear, or to cause a material amount of scaling orpitting of such parts.

Although the foregoing description has been concerned with securing avalve seat in an engine part constructed of a material having a diHerentcoefficient of expansion, it will be understood that my invention is notlimited to such use, but may be employed, irrespective of the purposefor which it is empl-oyed, to secure a valve seat of any desirable metalin an engine part constructed of any metal adapted for suchv use.

j It willbe understood that various changes and ymodifications inconstruction may be resorted to Without departing from the spirit andscope of my invention.

I claim as my invention:

1. A valve seat unit for an internal combustion engine comprising aninner portion of metal having a coeiiicient of thermal expansionmaterially different than the metal of the part to which the unit is tobe attached, and an external porti-on of metal having a coefficient ofthermal expansion similar to the coeiiicient of expansion of the metalof the aforesaid part.

bustion engine comprising 'an inner portion of metal having acoefiicient of thermal expansion materially different than that ,of castiron, and an external portion of nieta'l'having a coefficient of thermalexpansion similar to that of cast iron.

3. A valve seat unit for an internal combustion engine comprising anouter part of 2. A valve seat unit for an internal comsteel, and aninner part of aluminum-bronze alloy securely bonded to said outer part.

4. A valve seat unit for an internal coml bustion engine comprising aportion constructed of metal having a coeicient of thermal expansionsimilar to the coeilicient of expansion of the metal of the engine partto which the unit is to be attached, and designed for securement to theaforesaid engine part, and a portion constructed of metal having adifferent coeilicient of thermal expansion than the aforesaid enginepart, securely bonded to said first named parte, and formed with a valveseat surface.

5. A valve seat unit for` an internal combustion en ine comprising anouter art constructed 0% a metal havmg a coe cient of thermal expansionsimilar to the coefficient of thermal ex ansion of the metal of theengine part to whlch the unit is to be attached, and an inner portion ofa metal having a coefficient of thermal expansion different than themetal of the aforesaid engine part, .secured to said outer part by afused metallic bond, and formed with a valve seat surface.

6. A valve seat unit for attachment to a cast-iron part of an internalcombustion engine comprising an outer steel part, and an inner partconstructed of a metal having a materially different coeilicient of exanslon than the metal of the aforesaid castiron engine part, secured tosaid steel part by a fused meta lic bond, and formed with a valve seatsurface.

7. A valve seat unit for attachment to a outer ortion or said enginepart, securely bond to said outer portion by a fused metallic bond, andformed with a valve seat surface.

11. A valve seat insert for use in an internal combustion engine inconjunction with a poppet valve for controlling a breathing passage ofan engine, designed for securement `within an englne in a recess formedat the inner end of a breathing assage in circumambient relation to thereathing passage, said insert comprising a metallic ortion in the formAof a ring by which sai insert is 4 secured in place, and a' secondmetallic ortion constructed of a different metal t an said first namedportion, securely bonded to said first named portion by a fused metallicbond, and formed with a valve seat surface.

. In testimony whereof I hereunto aix my signature this 6th day ofNovember, 1930.

' GEORGE W. SMITH, Jn.-

cast-iron part of an internal combustion enginev comprising a threadedsteel part de'- si ed for threaded engagement with the a oresaidcast-iron engine part, and a part Y securely bonded to said steel part,constructed of a metal having a' materially different co-- eicient ofexpansionl than the metal of the aforesaid cast-iron engine part, andformed Y ferent metal thansaid first named portion,

securely bonded to said firstnamed portion, and formed with a' valveseat surface.

9. A valve seat unit for an internal combustion engine comprisingan-outer metallic portion, and an inner metallic portion cony structedof a different metal than said `rst named portion, secured to said firstnamed portion a fused metallic bond, and formed with a va ve seatsurface. A y

10. A valve seat insert for attachment to a cast-iron part of an,internal combustion engine comprising an outer steel portionconstructed in the form of a ring and designed for engagement with saidcast-iron engine,

part, an an inner annular portion, constructed of a different metal thaneither said

